Light sensor

Abstract

The light sensor has a plate-shaped light guide in which a plurality of reflection portions each comprising a V groove are parallelly arranged on one plane thereof. An end face of the light guide which faces the side surfaces of the V grooves is opposed to a light emitting face of a light emitter. Light receivers are disposed at an appropriate distance from the light guide so that the light receiving faces thereof are opposed to the other plane of the light guide. Light emitted from the light emitter is taken in the light guide, is reflected at the reflection portions, and is ejected from the other plane toward the light receivers. With the light sensor, the range of detection by one light emitter is large, it is easy to adjust the optical axes, and the number of provided light emitters can be reduced.

1 . A light sensor comprising: 
 a light emitter;    a light receiver for receiving light emitted from said light emitter; and    a light guide for taking in the light emitted from the light emitter, reflecting the taken-in light at a reflection portion provided on a part thereof, and ejecting the light toward the light receiver,    wherein the light receiver and the light guide are disposed so as to be opposed to each other with an appropriate space in between, and entry of an object into said space is detected based on the light received by the light receiver.    
     
     
         2 . The light sensor according to  claim 1 , wherein the light guide in a plate shape, which has the reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         3 . The light sensor according to  claim 2 , wherein the reflection portion has a groove shape.  
     
     
         4 . A light sensor comprising: 
 a light emitter;    a light receiver for receiving light emitted from said light emitter and reflected at a reflective object; and    a light guide for taking in the light emitted from the light emitter, reflecting the taken-in light at a reflection portion provided on a part thereof, and ejecting the light,    wherein the light receiver receives the light ejected from the light guide and reflected at the reflective object, and a position of said reflective object is detected based on the light received by the light receiver.    
     
     
         5 . The light sensor according to  claim 4 , wherein the light guide in a plate shape, which has the reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         6 . The light sensor according to  claim 5 , wherein the reflection portion has a groove shape.  
     
     
         7 . A light sensor comprising: 
 a light emitter;    a light receiver for receiving light emitted from said light emitter; and    a light guide for taking in the light emit ted from the light emitter, reflecting the taken-in light at a reflection portion provided on a part thereof, and ejecting the light toward the light receiver,    wherein the light emitter and the light guide are disposed so as to be opposed to each other with an appropriate space in between, and entry of an object into said space is detected based on the light received by the light receiver.    
     
     
         8 . The light sensor according to  claim 7 , wherein the light guide in a plate shape, which has the reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         9 . The light sensor according to  claim 8 , wherein the reflection portion has a groove shape.  
     
     
         10 . A light sensor comprising: 
 a light emitter;    a light receiver for receiving light emitted from said light emitter;    a first light guide for taking in the light emitted from the light emitter, reflecting the taken-in light at a first reflection portion provided on a part thereof, and ejecting the light; and    a second light guide for taking in the light ejected from said first guiding body, reflecting the taken-in light at a second reflection portion provided on a part thereof, and ejecting the light toward the light receiver,    wherein the first light guide and the second light guide are disposed so as to be opposed to each other with an appropriate space in between, and entry of an object into said space is detected based on the light received by the light receiver.    
     
     
         11 . The light sensor according to  claim 10 , wherein the first light guide in a plate shape, which has the first reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         12 . The light sensor according to  claim 11 , wherein the first reflection portion has a groove shape.  
     
     
         13 . The light sensor according to  claim 12 , wherein the second light guide in a plate shape, which has the second reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         14 . The light sensor according to  claim 13 , wherein the second reflection portion has a groove shape.  
     
     
         15 . The light sensor according to  claim 10 , wherein the second light guide in a plate shape, which has the second reflection portion disposed on one plane thereof, takes in the light through one end face thereof, reflects the taken-in light at the reflection portion, and ejects the reflected light from the other plane thereof.  
     
     
         16 . The light sensor according to  claim 15 , wherein the second reflection portion has a groove shape.